Microphone.



No. 666,677. Patented Ian. 29, MN. ALFRED GOODRIGH HOLCOMBE, Decd.

ALFRED GILLETTE HULGOMBE. Administrator.

MICROPHONE.

(Application filed May 16. 1900.)

(No' Model.)

IIIIIIIIIIIIIIHIV 1 I V'VFTNESSES': A I7107ZZF i I Y ATTORNEY Tu: uonms PETER: co.. moroufna, wmmnfou, 04 c.

UNITED STATES PATENT EEICE.

ALFRED GILLETTE HOLCOMBE, OF SOUTHAMPTON, MASSACHUSETTS, ADMIN- ISTRATOR OF ALFRED GOODRICH HOLCOMBE, DECEASED.

MICROPHONE.

SPECIFICATION forming part of Letters Patent No. 666,677, dated January 29, 1901.

Application filed May 16, 1900. Serial No. 16,881. (No model.)

To aZZ whom it may concern.-

Be it known that ALFRED GOODRICH HoL- COMBE, deceased, late a citizen of the United States and a resident of the town of Hempstead, county of Nassau, State of New York, (ALFRED GILLETTE HoLcoMBE,of Southampton, Hampshire county, State of Massachusetts, administrator,) did invent certain new and useful Improvements in Microphones, of which the following is a specification, reference being had to the accompanying drawings, forming part thereof.

This invention relates to microphones; and it consists in the provision of an independent device adapted to be operated by a connection with a diaphragm which vibrates under the influence of sound-waves. The device is arranged to be mechanically connected to a diaphragm and to partake of its movements; but the diaphragm is not an element of the device per so, as is usual. The microphone has arranged therewith a movable pressure device preferably loosely mounted therein and adapted to vibrate sympathetically with the diaphragm, but to have no direct connection with it. The result of such arrangement and one of the main objects of the invention is that a plurality of microphone units made according to the invention can be used in connection with one diaphragm. By arranging the same in multiple electrically and by increasing the battery-power proportionately a current can be used which will overcome any resistance likely to be encountered. In the preferable form of the invention one of the said microphone units consists of two relatively stationary members and a movable member arranged to vibrate with respect to the stationary members, there being a quantity of electrically-conductive material between the said stationary members and the movable member. A microphone made in this manner is self-contained and capable in itself of taking up vibrations from the diaphragm, but is itself independent of the diaphragm.

The invention further consists in an improved means for connecting a plurality of microphone units to a single diaphragm; and the invention further consists in certain details of construction and combination of parts, as will be hereinafter more fully set forth.

The invention will now be described with reference to the accompanying drawings, and the novel features will then be pointed out in the claims.

Figure l is a central longitudinal section of a microphone embodying the invention, showing the same secured to a diaphragm. Fig. 2 is a central transverse section of the same. Fig. 3 is a view illustrating a plurality of microphone units arranged to operate in connection with a single diaphragm.

The diaphragm a is adapted to receive and transmit vibrations and may be, for instance, the transmitting-diaphragm of a telephone. This diaphragm may be of any suitable material; but it has been found that a wooden diaphragm gives very good results, and hence the diaphragm is preferably of wood.

The improved microphone b as a whole is itself an independent device and may be secured to partake of the vibrations of the diaphragm in any suitable manner. The diaphragm is not an element of the microphone per so, as is usual, but merely has such connection with it as will transmit its vibrations thereto. The result of such arrangement is to permit the connection of a number of microphone units to one diaphragm.

The microphone 1) comprises two members 0 and d, held relatively stationary to but out of contact with each other. The members 0 and d are cup-shaped and are arranged with their open ends toward each other. They are of electrically-conductive material and are connected the one with the positive side of an electric circuit and the other with the negative side thereof. The material of which they are composed is preferably carbon or some analogous material which will conduct electricity, but which will not readily oxidize, and it is convenient to copper-plate the exterior surface thereof, the effect of copper-plating the exterior being to increase the longitudinal conductivity. The said members 0 and dare held relatively stationary to, but out of contact with, each other by a cylinder of nonconducting material 6. This outer covering is conveniently formed of paper coated with shellac; but it may be of any suitable nonconducting material.

A movable member fis arranged within the stationary cup-shaped members 0 d, and between the movable and the stationary members is provided a quantity of granulated electrically-conductive material g, such as granulated carbon. The movable member f is suspended about centrally in the granulated material and is preferably of some electrically-conductive and non-oxidizable material, as carbon, but not necessarily so. The said movable member f may be termed a pressure device. When the relatively stationary members are vibrated by reason of their connection with the vibratory diaphragm, the movable member is sympathetically vibrated; but by reason of the fact that on account of its inertia it will start to move a little later than the members 0 and d and in consequence of the momentum acquired will still have a forward tendency at the moment the members a and 01 start to return the said movable member will act as a pressure device, pressing the granulated material between it and the said relatively stationary members.

One of the stationary members,- as c, has secured to it a button 71, which acts as an electric terminal, to which may be secured, say, the positive side of an electric circuit, and the other stationary member, as d, has secured theretoasimilarbnttonLwhich acts as an electric terminal, to which may be secured in like manner the negative side of an electric circuit. The buttons 7t and dare of electricallyconductive material, such as copper. A strap or bandj is shown, by which the microphone may conveniently be secured to the said diaphragm.

The parts of the microphone may conveniently be assembled as follows: The member 9 may be set on end with the open end upward, and it may be filled with granulated material and the movable memberf inserted therein. The second member d may be inverted and held in position above the memher 0, and the sheathing 6 may be secured in position, thus holding the members 0 and d in correct relative position. The member (1 is conveniently provided with an orifice 10, through which sufi cient granulated material may be inserted to fill up between the two members 0 and d and within the member (1 around the movable member f. The buttons h and i now being secured to the members 0 and d, the microphone is ready for use. The securing of the button 11 to the member (2 closes the orifice 7i; and effectually seals the same.

Fig. 3 illustrates the method of using a plurality of improved microphone units in connection with one diaphragm. Ct designates the diaphragm, and b b the microphone units. Z on designate two metallic strips which form the positive and negative terminals for the electric current. At opposite ends they are mounted on insulating-blocksno. The front block 'n is connected to the diaphragm a by means of a short connecting-rod, and the rear block is connected in similar manner to a diameter.

spring-stripp. Suitable means, asby threading a portion of the connecting-rod and providing an adjustingnut therefor, may be arranged for adjusting the tension of. the spring p.

Any desired number of microphone units may be employed and connected in multiple, as shown and described. The electric current may be increased proportionately to the number of units employed, and by this means a microphone of immense power, but of great delicacy, may be obtained.

It is preferable to make the microphone units of very small size, the members 0 and d not more than about one-half an inch in Thus a number may, if desired, be secured to one diaphragm in the manner shown in Figs. 1 and 2.

It is evident that various modifications of construction may be made within the purview of this invention.

What is claimed, and desired to be secured by Letters Patent, is-

l. The combination, with a diaphragm adapted to vibrate under the influence of sound-waves, of a self-contained microphone, capable in itself of taking up vibrations from the diaphragm but itself independent of the diaphragm, and comprising a positive and negative member of electrically-conductive material, held out of contact with each other, and an independent pressure device and granulated electrically-conductive material arranged between the pressure device and the said members, substantially as set forth.

2. The combination with a vibratory part, of a microphone having two members of electrically conductive material connected to such vibratory part so as to partake of the movements thereof and held relatively stationary to and out of contact with each other, and a third member not connected to such vibratory part and arranged to have movement with respect to the first two members, and granulated electrically-conductive material arranged between the relatively stationary members and the movable member, substantially as set forth.

3. The combination with a vibratory part, of a microphone having two members of electrically conductive material connected to such vibratory partso as to partake of the movements thereof and held relatively stationary to and out of contact with each other, and a third member loosely arranged with respect to the first two members and the vibratory part, and granulated electrically-conductive material arranged between the said relatively stationary members and the loose member, substantially as set forth.

4. In a microphone, the combination with two cup-shaped members of electrically-conductive material, held relatively stationary to but out of contact with each other, the open ends thereof being toward each other, of a loose kernel arranged within and between said cup-shaped members and granulated electrically-00nductive material arranged between said cup-shaped members, and the said loose kernel, substantially as set forth.

5. In a microphone the combination with two cup-shaped members of electrically-conductive material held relatively stationary to but out of contact with each other, the open ends thereof being toward each other, of a loose kernel of electrically-conductive material arranged within and between said cupshaped members, and granulated electricallyconductive material arranged between said cup-shaped members, and the said loose kernel, substantially as set forth.

6. In a microphone, the combination with two cup-shaped carbon members held relatively stationary to, but out of contact with each other, the open ends thereof being toward each other, of a loose kernel arranged within and between said cup-shaped members, and granulated carbon arranged around said loose kernel, and between it and the cupshaped members, substantially as set forth.

'7. In a microphone, the combination with two cup-shaped carbon members having their outer curved surface copper-plated, the said ,members held relatively stationary to, but

out of'contact with each other the open ends thereof being toward each other, of a loose kernel arranged withinand between said cupshaped members, and granulated carbon arranged around said loose kernel, and between it and the cup-shaped members, substantially as set forth.

8. In a microphone, the combination with two cup-shaped members, of a cylindrical sheathing of electrically non-conducting material in which the said cup-shaped members are mounted and by which they are held relatively stationary to but out of contact with each other, of a loose kernel arranged within and between said cup-shaped members and granulated carbon arranged between said loose kernel and said relatively stationary members, substantially as set forth.

9. In a microphone, the combination with two cup-shaped members of electrically-cond uctive material, and means whereby the said members are held relatively stationary to but out of contact with each other, of a loose kernel arranged within and between said cup-shaped members, and granulated electrically-conductive material arranged between the said loose kernel and the cupshaped members, one of the said members having an orifice through which the granulated material may be inserted, substantially as set forth.

10. The combination, with a diaphragm, of a plurality of microphone units, each unit having a positive and a negative member arranged relatively stationary to each other but adapted to partake of the movements of the diaphragm, an independent member for each unit, arranged to have movement with respect to the said stationary members, and granulated electrically conductive material arranged in each unit between the said relatively stationary members and the movable member, substantially as set forth.

11. The combination, with a diaphragm, of a plurality of microphone units electrically connected togetherin multiple, each unithaving a positive and a negative member arranged relatively s'tationary to each other but adapted to partake of the movements of the diaphragm, an independent member for each unit, arranged to have movement with respect to the said stationary members, and granulated electrically-conductive material arranged between the relatively stationary members and the movable member, substantially as set forth.

12. The combination, with a diaphragm, of a plurality of microphone units connected to said diaphragm and arranged to vibrate there-.

with, each unit having a positive and a negative member, held out of contact with each other, a pressure device held out of contact with such members, the said pressure device being capable of taking up vibrations from the diaphragm,but itself independent thereof, and granulated electrically-conductive material arranged between the pressure device and said members, substantially as set forth.

13. The combination, with a diaphragm, of a plurality of microphone units together mounted in an independent movable frame, a mechanical connection between one end of the frame and the diaphragm, a spring secured to a fixed support, and a connection between the opposite end of the frame and the said spring, substantially as set forth.

14:. The combination, with a diaphragm, of a pluralityof microphone units, an independent movable frame in which said units are mounted, a connecting-link between one end of the frame and the said diaphragm, and an adjustable spring connection with a fixed support for the opposite end of the frame, substantially as set forth.

15. The combination, with a diaphragm, of an independent movable frame comprising two metallic strips and two blocks of electrically non-conductive material all secured together, a plurality of microphone units each having two electrical terminals,each unit having one terminal attached to each metallic strip, a connecting-link between one of the said blocks and the said diaphragm, aspring secured to a fixed support and a connection between the other of said blocks and the said spring, substantially as set forth.

Sign ed at Southbridge,county of Worcester, State of Massachusetts, this 7th day of April, 1900.

ALFRED GILLETTE HOLOOMBE, Administrator of the estate of Alfred Goodrich Holcombe, deceased.

Witnesses:

MORRIS H. MAROY, ALFRED E. COLE. 

